01 - Preheat oven to 400°F.
02 - Slice the top off the garlic bulb to expose the cloves. Drizzle with olive oil, wrap in foil, and roast for 30-35 minutes until soft and golden. Let cool slightly.
03 - Steam cauliflower florets over boiling water for 12-15 minutes until very tender. Drain well and allow to release excess moisture.
04 - Squeeze roasted garlic cloves from skins into a food processor or large bowl. Add steamed cauliflower, butter, sour cream, milk, salt, and pepper. Blend or mash until smooth and creamy.
05 - Taste and adjust seasoning as desired. Stir in half the chives, transfer to serving bowl, and garnish with remaining chives.